Gyroscopic slaving apparatus



Sept. 9, 1952 w, STONE 2,609,693

GYROSCOPIC SLAVING APPARATUS Filed Sept. 9, 1949 lO-GYROSCOPE WAYNE A. STONE (I ttorneg Patented Sept. 9, 1952 2,609,693 a ornoscoric SLAVING APPARATUS Wayne :A. StoncgSt. Louis; Park, Minn, assignor to Minneapolis-Honeywell;Regulator Company, ,Minneapolis, Minn, a corporationvof Delaware Application September 9, 1949, Serial N0;-?114;7-3'7 pass, through asuitable 'deviation resolvencontrolling the' precession of thergyroscope to correct for such wandering. 'In such apparatus, the precession rate of the gyroscope iskept flow so' 'thatthe gyroscope will not respondfto oscillations of the compass' but will only be iprecessed unsteady-deviations.

when a :slaving apparatus"isi initially placed into operation, :as for example at-thestart of a night; or when the slaving apparatus is I established aftera period of unslave'cl operationuof the gyroscope, there is'usually :a :Wide deviation between the compass and gyroscope. With lthe normal rate 0f precession of the gyroscope, the time required to effect a ignment between the gyroscope and. the compass is undesirably large.

Therefore, the present invention is dESigDBd'ntO provide a :novel means of reducing the time re- 'quired for alignmentof the gyroscope and compass .under suchcircum'stances. With the apparatus =of the present invention; the :gyroscopemetain's' its normal rate of precession for normal operation and whererequirecl an auxiliary ;circult-is initiated to brake thespeed of rotation o'f 'the gyroscope'to a pointwhere a ifas'terrate of control is obtained from the precession :motors.

Another object of this invention .is to provide a' slaving apparatus in which the efiectiveness of the gyroscope to align itself with thecompass is 1 increased under certain conditions.

It iis also an object of this inventiontovpro- :vi'deia slaving apparatus in i which :a means for increasing the speed 1 of alignment between the components of the apparatus is capable of manual initiationonlywhere there is a need foroperation :of the apparatus and is automatically terminated uponi satisfaction :of the :need for the operation-of the-apparatus.

" lt is further an object of this invention to provide in a gyroscope compass slaving z-appatems a braking circuit by which :a D. C. .:source isxconnected. to a windingoflthezrotor pf'itheigyroe scope/and a holdingcircuit to "sustain the 'br.aking circuit is completed by means of which a voltage generatediin anotherwwinding:qf iih xr lip energizes and :maintains the holding :Qircuitnas long as the rotor is-rotating above a :predeter: minedtspeed.

It :is .still further xanrobjectrof :this invention to m'mtide in a slavin apparatus foraa gyr sc pe anti-a compass, a means for brakingthe speed i of rotation of the gyroscopetodecrease ther me required ;,for;alig;nment of the compass nd e yroscope, this ,{means b in auto aticaly- 0.0 :trolled 1 0 terminate the braking of hereyrcscnne at a iprede r nedrspeed so :thatvstabilityiqfvthe gyroscopewill be retained ,It is also an object of thisinventiontaprovigle a osc p cont llin app atu a W rSPGfld control for positioning the gyroscope, one "of which-is operative normally and the othernof which is manually initiated and automatically terminated upon the lack :of need for controlling the gyroscope.

These iand other objects :of; this inventioniyvill become apparent from; a reading; ofthe attached description together*withthedrawings, in which:

The fi gure is a circuit ,diagram (ofithe gyro scope icontrolling apparatus of vthe ,sulojectsin,- ,ventionand r i Referring to .thefigure, it will baseen ithatathe slaving apparatus tor the, subject invention geomprises essentially a gyroscope ,1 Hand a magnetic compass all together with. connecting. circuit meanszto accomplishthe slaving operation. The combination 10f a,gyroscope anducompass with a slaving circuit ris. commonly known as stabilized direction indicators ,or compass stabilized directionalwunits, this combination havin nurnero us applications in the ,fielclvofcontrol of air and water (craft either for an indicati g or apolitrqlline .iunction. While the subject rdisclosure e ates t imu d re t onal i dica on and slaving through a directional gyroscope; it should be noted that 'thegslaving apparatus ofgthe sub- ;J'ect invention can be appliedto stabilization of a gyroscope about other axe than th-at of azimuth "and this disclosureshould 'be considered as illustrative only. i

i -lie directional gyroscope 0f the subject s'lav ing apparatus is of the; conventionaliztype and includes ;a leasing :tfii "which: :housesua l'0liO1:;'(IID .C :sh'own) supported. EfOllLlOtfitidD. about :a JhOTiZDD- ital axis Withinthe casing. Whileitis notyshown. it shouldEbeiassumechthat the trotonof .the gtrmtscopeiisgofxthe types-showniimthezpatentrt Schoeppel 2,438,621 dated March 30, 1948. The spinning means of the rotor is a conventional two-phase induction motor which is connected as a conventional split phase induction motor energized from a single phase source. The drawing shows the windings of the induction motor field diagrammatically within the casing i2 which is connected into the subject slaving apparatus in a manner to be later described. Casing i2 which houses the rotor and its spinning means or mo-' tor is carried by trunnions 3 mounted in a gimbal ring M, the bearings for the trunnions being omitted from the disclosure since they form no part of this invention. The gimbal ring i4 is in turn mounted in and journaled by bearings l5 (only one of which is shown) through its trunnions IS. The lower trunnion of the gimbal ring is extended and carries a rotor element ll of a signal generator 20 which will be more fully de-' scribed as the disclosure proceeds. The bearings journaling the gimbal ring I 4 are to be assumed as mounted on the frame of the gyroscope for the purpose of pivoting the gyroscope in a vertical axis for displacement in azimuth.

I Gyroscope I0 is further provided with a precession motor 2| which may be a two-phase induction motor of the conventional type. Although not shown in the drawings, the precession motor 2| is assumed to include a rotor of the squirrel cage type carried on the trunnions I3 which mount the rotor casing ll of the gyroscope. A cooperating stator (also not shown) of precession motor 2| is mounted on the gimbal ring |4 to "cooperate with the squirrel cage rotor element of the'precession motor 2| applying a torque to casing |2 about the axis formed by trunnions [3 to cause precession of the gyroscope about an axis formed by trunnions It. Like the spinning mo- 'tor or means of the gyroscope, the precession motor 2| is assumed to be connected as asplitphase capacitor type induction motor in the manner shown in the Keeler Patent 2,272,914 issued February 10, 1942. a

-- "Precession motor 2| is controlled through a compass amplifier '23- of the type shown in the patent to A. P. Upton 2,243,534 dated July 8, 1947. Compass amplifier 23 includes an A. C. signal in- 'put at terminals 24, 25 and an A. C. power input at terminals 25, 21. Compass amplifier 23 also "includes a pair of discriminating relays 30, 3|

which are alternately operated dependingupon the phase relationship between the signal input and the power input as is shown in the Upton patent referred to above. The relays 3|], 3| have a pair of contacts 32, 33 respectively which, similar to the above named Keeler patent, connect the windings of the split-phase induction field of the precession motor 2| and its condenser in one manner or another to vary the direction of energization and hence the direction of the rotating flux field of the precession motor, the condenser being assumed to be located in the field of motor 2 I. Conductors 34, 35 connect the windings of the precession motor 2| to the relays 30,

windings of the precession motor 2| which are grounded at a common point 38.

The discriminating operation of the relays 30, 3| which control the direction of the rotating fiux field of the precession motor 2| and hence direction of its applied torque is controlled by the compass amplifier 23 as it responds to the phase relationship of the power and signal input. The power terminals 2'6, 21 are energized from the A. C. ships source. The signal terminals 24, 25 are connected to the single phase winding I! of the signal generator or transformer 20 from which the signal voltage is supplied. Terminal 25 of amplifier 23 is connected to winding I! by means of a conductor 45 and the opposite extremity of winding I1 is grounded at 46. Signal input terminal 24 is grounded at 41 to complete the circuit between the single-phase winding and the input terminals of amplifier 23.

Signal transformer 23 includes in addition to the single-phase winding on the rotating element [1, a three-phase winding 50 connected in a standard Y connection. As was previously noted the single-phase winding I! is carried on the lower trunnion N5 of the gimbal ring M of gyroscope Ill. The three-phase Y connected winding is stationarily mounted with respect to the movable portions of the gyroscope. This three-phase winding 5|) of signal transformer 20 is connected to a signal generator 5| carried by the magnetic campass Signal generator 5| is similar in construction to signal transformer 20 and includes a single-phase winding 52 and a three-phase stator winding 53 connected in Y- connection. Single-phase rotating winding 52 of generator 5| vis mounted on the shaft of the compass I to be rotated therewith relative to the winding 53 which is stationary with respect to the movable portion of the compass. The threephase windings 55, 53 of signal transformer 2|] and signal generator 5| are connected by a plurality of conductors 55 which connect like extremities of the windings to one another. The single-phase winding 52 is energized from a ships source of A. C. supply through a switch 56;

the purpose of which will be later noted. The

synchronous generator 5| and synchronous transformer'2ll together constitute a differential means known as a synchronous system or a resolver. Upon disalignment between the compass H and gyroscope l0 and when the winding 52 is en ergized from the single-phase ships source through switch 55, the synchro system or resolver will transmit a signal output voltage at winding I! which output signal is variable in phase and magnitude. This output signal is supplied to the compass amplifier 23 through the input signal terminals 24, 25 to control the operation of the discriminating relays 30, 3| of the amplifier.

The operation of the synchro system or resolver is conventional, the voltage being supplied to winding 52 will be transmitted to the threephase windings 53 in varying degrees dependent upon the relative. position of the single-phase winding with the three-phase winding. These voltages in the three-phase stator element of the synchronous generator 5| are supplied to the three-phase stator element 50 of signal transformer 2|! where they induce in the single-phase winding an output signal which is proportional to the relative displacements between the two single-phase windings. This signal which controls the operation of the relays30, 3|;de-

termines in .eifect the direction in which the rotor is energized,

5 torque ot the recession-motor 21 :is #to be applied; Relays -3ll 3l through the contacts 32,33 energize" the windings of thesinduction motor field of precession motor 2-! fromth'e-single-phase source of 1 secondary winding 31 tocause precession 'of the gyroscope -H! in a' direction to align the compass H and gyroscope H], or the singlephase Winding H with the single-phase winding 52 of the transmitter andgenerator respectively. Procession of the gyroscope throughithe operation of the precession'motor'll ,Chowever, is dependent upon rigidity 1 of the gyroscope which is -'obtained through rotation of-the rotor ofthe gyroscope.

The rotor of the gyroscope; as' noted above, is actuated by an inductiontmotor or a "split-phase typ'epa schematic disclosure f the windings of the rotor being shown and num'bered 6!! and 1. Thi's induction motor is similar to the induction motor field of the precession motor 21, the windings'60,61 beinggrounded at their common point, The-"windings B9; 54 are connected by conductors 63', 6'4 througha switch or relay 65 to a secondary winding {66 of transiormer lmthis secondary winding supplying a single-phase source oi power. The rotor of the gyroscope is designed for :a single direction of rotation and is not reverslble. A condenser 61 is connected in series with the windingtl and the source-"of power while the winding 60 is directly connected to the source of power to give a conventional split-phase master type induction motor circuit. Switch 65 through which the serves to disconnect the secondary "winding 36 it of transformer All and the condenser '61 from the rotor winding as will be later noted. In the'deenergized position, switch B=causes a' pai'r of normally closed contacts 10, II to connect'the windings 60,15! of the rotor induc tion motor to the condenser 61 and secondary windingBG-of transformer 40 through the following-circuit: secondary winding 66 of transformer 40, conductor I2,normally closed contact H! of switch 65 which includes the stationary. and movable portion of this contact, conductor 63 to winding 60; groundconnection 62' to a ground con- :nection '73 of secondary winding ii-6; and secondary winding 8B; conductor'n; conductor 15, condenser 61, conductor li'normally closed contacts 'Hof 'switch 65 whichincludes the movable and stationary portions of this contact, conductor 64; windings 1, ground '62, to ground connection '13 or secondary winding 65; v

The switch or relay 65 'is controllably positioned by "an electromagnet the coil of which is shown schematically at T6; In its deenergized position, the normally closed contacts M, H, switch 85 maintain the A. C. energization circuit for the gyroscope rotorrasoutlinedabove. The coil :of switch 651s energized through a pair of contactstll, Iii-of relays 35.31 respectively of compass amplifier 23 which are connected in series with the coil Wu and; a .momentary manually, operated switch 86 to control the energization-of the coil [6 from :a single-phase source :of

power suppliedby secondary winding 8! of transformer (it; This circuit is as follows: secondary winding 8!, conductor 82, contacts I1, 78 l.of --compassamplifier 73, to a conductor 83, coil 76,conductor-84, switch blade 850i momentary switch at; to a ground connection 86 and a ground connection 81 0f secondary winding 8|. Relay or switclrfifi is thus :energized through the above circuit from transformer secondary 8| .when manual switchsilfl lisrclosed closing the contactyor .switchmlade K851131101 when one or r the otherof thelrelay contacts "L11 18 ro'f trel'ays :31] 13.1 of compass amplifier :are closed? When ener-= gized, the normally closed contacts of'switch 65 are opened and hence the circuit for the energi zation of the :gyro rotor from the transformer secondary 66 is broken :atthe normally closed contactsm; 3!. A normally open contact Bllof switch (S5 is closed when the switch65 is enersized and the holding circuit .is established for the switch t5 around the momentary switch blade 85 through this contact. This holdingcircuit merely shunts :out the momentary contact switch bladelfiiiloymeans of axconductdr 9! connected to the ground connection86and through the normally closed contact 90 of :switch B5 conductor 84. nssumingone or :the other of the relays siL tl of the compass amplifier to be oper ated, the momentary contact of switch blade 85 of switch 80 will be shunted out of theenergization circuit for switch 65 by meansof the above described holding circuit when litheucontacts 'of switch 65 move to their energized positions close ing their normally :open contacts. In thissman= nor the relay fiii once energized "will remainenergized untilthe relays3 fl, 31 or icompassiamplifier 23 areboth deenergized.

The switch of relay 85 in addition :to perform-- ing the function of disconnecting the =rotor=wind+ ings from their A. C. source when it=is energ-ized,. further connect a D. C. source 1100 "to itherotor winding Bil in a circuit which will be 1 later described. As switch-"65 isenergized, .aspairmf normally open contacts l (H and J52 respectively are closed, these contacts having a common mov able element with the i normallyiclosed contacts "19,2! and being connected to conductors G3, 64 common to the rotor windings 60, 'Bl The DC. supply lllfi is connected to the windingtll through a normally open contact I63 of a relay ll M which is connected to the normally open contact 10! of relay 65 by means of .a'conductor Hi5 and through the normallyopen contact ml, the con doctor 63 to the winding 63. Although not shownin the drawing, the'Dr'Clsourceisassumed to have ltsnegative terminaltgrounded such-that the circuit through the windingl fiil is complete through the ground connection 62 to the grounded D. C. source: The relay l 04 whose: normally open contact ms "controls the energization of winding Sil from the'D. C. source isrprovided for the purpose of disconnecting the D. C. source -from said rotor windingiunder certain conditions independent of the operation of relaytS. Relay iiit is also energized initially from the secondary winding 8| of transformer '40 through ai'second switch blade I66 of momentary switch Bil iinra circuit as follows: secondary winding 8|,"conductor 1m, Switchblade l 66 of momentary switch 88, conductor Hi3, relay coil ill of relay 'lll4, ground connection H2, to ground connectionill of winding 31. The switch bladeshlilficand fi of momentary switch '8!) are mounted for ganged operation such that they operate simultaneously although electricallyindependent ofoneanother. Thus when themomentary switch 80 is made, therelay lfl i will be energized to close its normally open contact Hi3 'and the switch or relay "65 will he energized dependent upon the energiz'ation- 'o'f one or the other of'relays 3U, 31 of compass amplifier 33 to disconnect the-rotor from its "A. C. source and complete the energizationto the 'D. C. source I00.

Since the operation of switch 80 is intended to be momentary only, that is its switch blades 85 and :lllfirare biased to anlopen position,zthe energization of relay I04 from the secondary winding 8| .of transformer 40 will similarly be momentarily dependent upon the position of switch blade I06. A holding circuit for this relay is provided which instead of shunting out the switch blade I06, is one which connects the relay coil II I to a new source of power such that the relay I04 will remain energized as long as the new source of power is present. In this respect the relay coil I is connected through the conductor I ID to a conductor I I3 connected to the normally open contacts I02 of switch 65. The normally open contact I02 as noted above, has a common movable element with the normally closed contact II and is connected to the conductor 64 leading to the winding 6| of the rotor induction motor. Since the opposite extremity of winding BI and the opposite extremity of coil III are grounded, this circuit will be complete whenever relay 65 is energized.

Thus when relay 65 is energized through the manual momentary switch 80 under control of the'relays 30, 3| of the compass amplifier 23, the A. C. source from the secondary winding 66 of the transformer 40 will be disconnected from the winding 60, 6| andthe D. C. source I will be connected through the normally open contacts of relays I04 and 65 to the winding 60 of the rotor induction motor. Similarly the windings 6|will be connected in circuit with the winding I I of relay I04. The D. C. source when applied to the winding 60 of the rotating rotor will cause a dynamic braking effect upon the rotor, and the direct current flowing in the winding 60 together with the rotation of the rotor caused by its angular momentum will generate in winding 6| an A. C. signal which will be transmitted to the winding I II energizing the same. This winding which was initially energized through the switch blade I06 of manual switch 80 from the secondary winding SI of transformer 40 will thus be held in its energized position from the current generated in the rotor winding 6| even though the momentary switch contact is opened cutting off theA. C. supply from the secondary winding 8|. The voltage generated in the winding 6| will be. dependentupon speed of rotation of the rotor since the D. C. supply is fixed and as the dynamic braking effect slows the rotation of the rotor, the voltage output of winding 6| to the coil III of relay I04 will correspondingly be decreased. As the voltage output of winding 6| drops below the normal drop-out voltage of the relay I04, this holding circuit will become ineffective and will disconnect the D. C. supply from the rotor winding 60 through the deenergization of relay [04. At this point dynamic braking action caused by the D. C. supply to the rotor winding 60 will be terminated and the rotor will spin freely being slowed down only by inherent friction and windage. The relay I04 is designed to have a voltage drop-out such that the speed of the rotor of the gyroscope will not be brakedbeyond a particular speed of rotation at which the'operation of the precession motors will have the greatest effect. In this manner the rigidity of the gyroscope will be retained during the rapid precession operation of the slaving apparatus and upon resumption of normal operation of the slaving apparatus the gyroscope can be brought up to normal operating speed in a shorter period of time.

Operation The operation of thisslaving apparatus is undesirable factor.

based on the known principle that theefiect of the precession motors can be increased by de: creasing the angular momentum or speed of rotation of the gyroscope rotor mass. The less rigid the gyroscope is inherently, the greater the eifect of the torque of the precession motors becomes.

Under normal operation the slaving apparatus is largely conventional. With the resolver circuit energized, any variance or disalignment between compass andgyroscope will be evidenced by a signal on the rotor winding II of the signal transformer 20 which signal will-control the operation of the compass amplifier 23 and :its' associated discriminating relays. These relaysin turn control the energization of the precession motor 2| to cause precession of thegyroscope at a normal low rate which is not subject to oscillation of the compass element but responds only to the steady-state deviations. Under normal slaved operation no wide degree of disalignment will .be present since the resolver circuit working through the compass amplifier and precession motor will continuously correct for any wandering of the gyroscope precessing or slaving it to the compass. Under such circum': stances; there is no need for operation of the remaining portion of theapparatus.

Assume now that for an extended period 'during the flight or voyage that the gyroscope-be operated in an unslaved condition, that is with the resolver circuit deenergized. Such unslaved operation of a directional indicator or a directional component of a steering apparatus is not unknown or unusual since compass error at extreme northern and southern latitudes is highly disadvantageous and best overcome by such unslaved operation. After such a period of operation when the slaving apparatus is again initiated the time required for realignment of the gyroscope and compass would ordinarily be another In the present invention rapid alignment is obtained merely by engaging the momentary switch which energizes the relay 65-and' I04 to disconnect the induction mo,- tor field of the rotor from its A. C. source and cone nect the winding 60 of this field to the D. C. source I00. With the relays thus operated, the dynamic braking of the rotor is initiated and the rotor speed is decreased, thereby increasing the eifectiveness of torque motors in realigning the gyroscope with the compass. As the D. C. is applied to the rotor winding 60, a voltage is generated in the rotor winding 6| which will maintain the relay I04 energized after the momentary switch 80 is opened. As noted above the relay 65 is held closed by means of the holding circuit through the normally open contact of relay 65, this holding circuit maintaining the energization of the coils 16 of relay 65 as long as there is disalignment between gyroscope and compass and one or the other of the relays 30, 3| of the compass amplifier 23 is energized. As the rotor speed decreases, there is a corresponding decrease in the voltage generated in winding 6|. Should this voltage fall below the drop-out voltage requirment of relay I04, this relay will become deenergized and the D.' C. source will be disconnected from the rotor winding 60. Assuming that alignment has still not been attained, the rotor will continue to rotate freely at this lower speed being slowed down further only by windage and frictional losses. During this period the increased effect of the precession motors causes "a rapid alignment between: gyroscope and comwhen this. alignmcntis attained, the resolyer circuit will no. longer supply; a signal Iromrits-rotor. winding. H of. signahtransformer 2.0:.and-hence the compass amplifier. and its associated discriminating relays 30, 3| will become deenergizedthereby openingthe energization circult for. the relay-'65; At this pointthe relay 65 moves to. its" deenergized; position where its normally. closed contacts are closed: and A. C. is again applied to the rotor toacoelerate it toits normal operating speed.

It...during. the dynamic braking period .of the rotor alignment-is attained, between the gyroscope [B and com-pass, llbeiorethe rotor has reached thezpredeterminedspeed levelat which the Dr C.

source isdisconnectedthereirom, the resolver circuit -will discontinue its signal supplied to the compasscamplifier; 23,. andits associated relays will-moves to the :deenergizedposition thereby causin the. relay 65 to-become deenergized. As the relayor switch 65* moves to its deenergized position under these conditions, the normally open contact I 02 will openlbreaking the energizing. circuit of the-relay I94 from therotor winding 5| therebydeenergizing the relay I'M. Since. both therelaysl04 and 65 control the D. C. energize.- tion.circuit.for the, rotor winding Bil. either one will break this energization circuit. Upon such operation the normal A. C. energization circuit forthe rotor windings 60, El will again be established and the rotor will accelerate to its 1110]?- mal operating speed, the apparatus returning. to itsnormal operation. V

- Assumernow the condition of the-initial starting: oil-the gyroscope; Under such. circumstances 311i apparatus-in-the circuit wouldv be under a normal deenergized (position; and. the power. to the trans-former ll', the compass amplifier 23 of the resolver system-.woul'd be; connected from the ships. source through switches not shown; The

switch for the resolvercircuit \vould be in an unslaved position, that isthe switch 55 would be open-and this resolver circuit would be deenergizedalthough power wasv available-at the switch. As the transformer 46 is energized, A. C. will be applied to the. gyroscope rotor and itwill accelerate toward its normal operating condition. This period iscommonly known. as a warm-up. If there is amwide degree of disalignment between the compass and gyroscope, the slaving apparatus wi'll be energized at this: point through the switch 56. Since the time required for a gyro rotor to; accelerate to. its normal speed isusua'lly quite long, the establishment of theresolvercircult at this point will eilfect a rapid. rate of operation otthe precessionrmotor'. 2 l-in aligning. the compassnwith theg-yroscope. If, however, the alignment is not obtained before the. gyroscope hasacquired considerable momentum, the rate of a-ligment-Will be. correspondingly decreased. as the rotor speedincreases. Therefore itmay be. de sir-able. toengage the momentary switch Bflto disconnect-the A. Qsupply from. the. rotor and conmeet the D. C. source: to the rotor winding (iii-to 'eiiect. a. dynamicbrakin of therotor holding where the rotor hasnolonger a gyroscopic eifect, then the resolver circuit must be deenergized through. switch 56 to place-the relays 65 and IM in la deenergized position. Under such circumstances .A. C. will again be applied to the gyro rotor and an acceleration period will again be resumed. .Once the rotor has attained a speed with which it is stable, the apparatus of the subject inventionmay again be brought into play to eiiect a rapid alignment of the. gyroscope with therotor. V V a In considering this inventionv it should be kept in mind that the present disclosures intend to be illustrative only and the scope. of the invention should be determined only by theappended claims. 7 V a 1..In combination, a gyroscopeincluding; a rotor, and spinning means therefor ior normally spinning said rotor at a. predetermined speed, means for precessing the, gyroscope, .braking means for said rotor, manual means for initially rendering said braking. means eifective to reduce the speed of said rotor so as to decrease gyroscopic rigidity and increase theeifect of opera- 'tion of said precession means, and meansresponsive to a condition indicative of they rotor assuming a lower predeterminedspeed for automatically terminating the operation of-salid bralging means. V

2. In combination, a gyroscope including .a rotor. and spinning means therefor for normally spinning. said rotor at a predetermined speed, means for processing the gyroscope, means responsive to a first condition for controlling the operation of said precessingmeans to cause the gyroscope to assumes. position related tosaid conditiombraking means for said rotor, means for rendering saidbraking means effective to reduce the speed of said rotor and hence increase the eilect of operation of said precession means, means for terminating operation of said brakin means when the speedof said rotor is reduced to a predetermined extent,. and means operative when said gyroscope. assumes. a position corresponding. to. said condition? for causing the rotor speed .to be restored to said predetermined speed. V

'3. In a gyro compass slaving apparatus, a come pass, a directional gyro including a rotor with spinning. means therefor and precessionjmeans for. said, gyro, differential energizing means. responsive to angular displacement betweensaid compassand said gyro. for controlling said pre cession means, relay. means controlled by said dlfferentialenergizing. means for controlling the energization. ofsai'd' spinning means of said rotor froman. A, Clsource, said relay means being initially energized through a manuallyinitiated switch, second relay, means connecting a D. C. source to said spinning means of said rotor when said .first named relay means is: operatedT to. dis: connect said .A. C. source from said spinning means. of said rotor, said second relay .means being in'itially operated through, saidinitiating'. switch. and being maintained .from a signalgenerated by said spinning means of said rotor means when energized from said D. C. source.

,4. ma gyro compassslaving apparatus, a .directional gyroscope having a spinning means andtorque applying means for processing said gyro-,- scope, a l compass, meansincluding a relay means responsive. to angular displacement between said compass and. said gyroscope for controlling the energization. of. I said torque applying meansi -to 11 precesssaid gyroscope into alignment with said compass, means selectively controlling the energization of said spinning means from an A. C. source or the energization of a portion of said spinning means from a D. C. source, and means adapted for manual operation to control the operation of said second named means.

5. In combination, a gyroscope including a rotor and a spinning means therefor, means mounted on said gyroscope for controllably positioning said rotor, a first circuit means responsive to a need for controlling said gyroscope to automatically control the operation of said rotor positioning means, a second circuit means energizing saidspinning meansof said rotor from an A. C. source, relay means establishing in one position said second circuit means, a third circuit means for energizing said spinning'means from'a D.-C. source established through a second position of said relay means, and manual means for operating said relay means.

6. In apparatus of the class described, a gyroscope including a rotor and a spinning means therefor, means mounted on said gyroscope for controllablypositioning said rotor, a first circuit means responsive to a need for controlling said gyroscope to automatically control the operation oi said rotor positioning means, a second circuit means energizing said spinning means of said rotor from an A. C. source, relay means establishing in one position said second circuit means, and a third circuit means adapted to be so energized as to cause braking of said rotor to a predetermined speed, said third circuit means being established through a second position of said relay means by a manual switching means and being maintained only when said spinning means is rotatin above said predetermined speed, said manual switching means being efiective to operate said relay means only upon a need for con trol of said gyroscope.

7. In apparatus of the class described, a gyroscope including a rotor and a spinning means therefor, means mounted on said gyroscope for controllably positioning said rotor, a first circuit means responsive to a need for controlling said gyroscope to automatically control the operation of said rotor positioning means, a second circuit means energizing said spinning means of said rotor from an A. C. source, relay means establishing in one position said second circuit means, a third circuit means for energizing said spinning means from a D. C. source being established through a second position of said relay means, manual means for operating said relay means, and a fourth circuit means maintaining said third circuit means established only when said spinning means is rotating above a predetermined speed.

8. In apparatus of the class described, a gyroscope including a rotor and a spinning means therefor, means mounted on said gyroscope for controllably positioning said rotor, a first circuit means responsive to a need for controlling said gyroscope to automatically control the operation of said rotor positioning means, a second circuit means energizing said spinning means of said rotor from an A. C. source, relay means establishing in one position said second circuit means, a third circuit means adapted to be so energized as to cause braking of said rotor to a predetermined speed, said third circuit means being established through a second position of said relay means by a manual switching means,- said manual switching means operating said relay means only upon a need for control of said gyroscope, and a fourth 12 circuit means maintaining said third circuit means established only when said spinning means is rotating above said predetermined speed;

9. In a gyro compass slaving apparatus, a directional gyroscope having a spinning means and torque applying means for precessing said gyro scope, a compass, means including a relay means responsive to angular displacement between said compass and said gyroscope for controlling the energization of said torque applying means to precess said gyroscope into alignment with" said compass, means selectively controlling the energization of said spinning means from an A. C. source or the energization of a portion of said spinning means from a D. C. source, and means adapted for manual operation and effective upon the need for'operation of said torque applying means to control the operation of said second named means, said torque applying means becoming more effective to precess said gyroscope into alignment with said compass when said D. C. source is applied to said spinning means.

10. In a compass slaving apparatus for a gyroscope, a directional gyroscope including a rotor having a spinning means and a torque applying means for precessing said rotor in azimuth, a compass including a signal transmitter for slaving said rotor in azimuth, a signal receiver mounted onsaid gyroscope and connected to said signal transmitter for resolving angular displace ment between said compass and said gyroscope and producing a signal proportional to said angular displacement, means including a first relay means responding to said signal from said signal receiver for controlling the direction of energiza tion of said torque applying means for precessing said gyroscope rotor into alignment with said compass, a second relay means for connecting and disconnecting said spinning means of said rotor to an A. C. source controlled by said first relay means, manual switch means for initiating the operation of said second relay means to disconnect said A. C. source from said spinning means of said rotor, third relay means for connecting a D. C. source to said spinning means of said rotor controlled by said manual switching means, holding circuit means for maintaining said second relay energized on continued operation of said first relay means, and a Second holding circuit means including said second relay means for connecting said third relay means to saidspinning means of said rotor, the energization of said third relay means from said spinning means of said rotor being dependent upon the rotation of said rotor.

11. In combination, a gyroscope including a rotor and a spinning means therefor, means mounting said rotor and said spinning means for displacement about a pair of mutually perpendicular axes, means mounted on said rotor mounting for applying a torque to said rotor about one of said axes for controlling the position of said rotor about the other of said axes, a first electric circuit means responsive to the need for controlling said rotor about the other'of said axes to automatically control the operation of said torque applying means, a second electric circuit means for controlling the operation of said spinning means of said rotor to provide for increased effectiveness of said torque applying means, and manual means for initiating said second electric circuit means, said second electric circuit means being efiective only upon a need for control of said rotor about the other of said axes.

12. In combination, a gyroscope including a rotor and a spinning means therefor, means mounting said rotor and said spinning means for displacement about a pair of mutually perpendicular axes, means mounted on said rotor mounting means for applying a torque to said rotor about one of said axes for controlling the position of said rotor about the other of said axes, a first electric circuit means responsive to the need for controlling said rotor about the other of aid axes to automatically control the operation of said torque applying means, and manually initiated second circuit means for reducing the speed of said spinning means of said rotor to provide for increased effectiveness of said torque applying means.

13. In combination, a gyroscope including a rotor and a spinning means therefor for normally spinning said rotor at a predetermined speed, means for processing said gyroscope, means for reducing the speed of said rotor, manual means for initially rendering said speed reducing means of said rotor effective to reduce the speed of said rotor so as to decrease gyroscopic rigidity and 14 increase the efiect of operation of said precession means, and means responsive to a condition indicative of the rotor assuming a lower predetermined speed for automatically terminating the operation of said speed reducing means.

WAYNE -A. STONE.

REFERENCES CITED ihe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,560,428 Myers Nov. 3, 1925 1,640,549 Lamme Aug. 30, 1927 2,161,241 Bates June 6, 1939 2,344,126 Carlson Mar. 14, 1944 2,524,756 Braddon et a1 Oct. 10, 1950 FOREIGN PATENTS Number Country Date I 591,598 Great Britain Aug. 22, 1947 

